The use of ultrasonic imaging techniques to obtain visible images of structures is increasingly common, particularly in medical applications. Broadly stated, an ultrasonic transducer, typically comprising a number of individually actuated piezoelectric elements, is provided with suitable drive signals such that a pulse of ultrasonic energy travels into the body of the patient. The ultrasonic energy is reflected at interfaces between structures of varying acoustic impedance. The same or a different transducer detects the receipt of the energy and provides a corresponding output signal. This signal can be processed in known manner to yield an image, visible on a display screen, of the interfaces between the structures and hence of the structures themselves.
Numerous prior art patents discuss the use of ultrasonic imaging in combination with specialized surgical equipment in order to perform very precise surgical procedures. For example, a number of patents show use of ultrasonic techniques for guiding a "biopsy gun", i.e., a instrument for taking a tissue sample from a particular area for pathological examination, for example, to determine whether a particular structure is a malignant tumor or the like. Similarly, other prior art patents discuss use of ultrasonic imaging techniques to assist in other delicate operations, e.g., removal of viable eggs for in vitro fertilization, and for related purposes.
For example, U.S. Pat. No. 5,261,409 to Dardel shows a system for Doppler measurement of blood flow. An ultrasonic beam is reflected so as to be coaxial with a needle introduced to a vein, at an angle to the axis of the transducer itself.
Takano U.S. Pat. No. 5,090,414 shows a system wherein a "stab needle", i.e., a biopsy needle, is mounted parallel to an ultrasonic probe. The transducer pivots to generate a fan-shaped beam, broadening the field of view.
Wedel et al U.S. Pat. No. 5,088,500 show an ultrasonic probe to be mounted on a physician's finger. The mount is provided with a guide for medical instruments, e.g., for biopsy or the like.
Terwilliger U.S. Pat. No. 4,911,173 shows a biopsy needle pivoted with respect to an ultrasonic probe, so that its distal tip can be moved into the field of view of the ultrasonic transducer.
Seitz U.S. Pat. No. 4,877,033 shows a combination instrument for transvaginal ultrasound procedures. A molded plastic guide receives both the ultrasonic probe and the aspiration instrument used to remove eggs for in vitro fertilization purposes.
Law et al U.S. Pat. No. 4,742,829 is directed to a instrument for generally similar processes. A guide for a biopsy needle is attached to the barrel of an ultrasonic probe, again for imaging of transvaginal procedures.
U.S. Pat. No. 5,335,663 to Oakley et al and a continuation-in-part thereof, now U.S. Pat. No. 5,469,853 to Law et al, both commonly assigned with the present application, teach combinations of ultrasonic probes and sheaths therefor. In particular, the Law '853 patent shows a sheath having internal lumens for accommodating a biopsy gun in spaced parallel relation to an ultrasonic probe so that the probe can be used to image and identify the tissue being sampled. The sheath is circular, so as to be sealed to a conventional surgical port. Sealing is frequently desired in performing procedures in the abdominal cavity, in order that compressed gas can be introduced to the surgical site, inflating the cavity somewhat and providing the surgeon with room to work. The ultrasonic probe shown in the '853 patent is articulated, so that the transducer can be disposed at an angle to an organ, enabling certain additional flexibility in selection of tissue for biopsy and imaging purposes. See FIG. 40.
EP application 0 446 645 of Kopek shows a curved ultrasonic transducer for imaging the prostate. A biopsy needle can be coupled to the probe for sampling tissue thought possibly to be diseased.
Articulated ultrasonic probes wherein the transducer is also rotatable about its axis are shown in detail in commonly assigned U.S. Pat No. 5,413,102 to Oakley et al.
Of further general interest is U.S. Pat. No. 5,070,879 to Heres relating to ultrasonic imaging generally. Commonly assigned U.S. Pat. No. 5,503,152 to Oakley et al teaches further specifics of ultrasonic signal processing techniques for image generation.
U.S. Pat. No. 4,759,348 to Cawood teaches an optical endoscope coupled with a biopsy needle or the like.
Ginn et al U.S. Pat. No. 5,443,457 shows a technique for placement of a relatively soft catheter, so as to enable drug delivery to a specified desired region of a patient's body. A relatively rigid guide wire is first placed in the tissue of interest, and a soft catheter is then slid over the guide wire.